FIG. 1 depicts the four basic elements of hydronic forced hot water heating systems 100. A heated water generator comprising a hydronic boiler appropriately sized and fueled for the application. Hydronic Radiation for converting heated water into convective and/or radiated atmospheric warmth, suitable to the application. Hydronic Distribution comprising a configuration of pumps (circulators), valves, piping, and hydronic accessories to appropriately deliver heated water from the boiler to radiation. A control system for hydronic energy creation and distribution, typically comprising a boiler aquastat and thermostatic radiation control.
Hydronic Heating System Configuration and Installation
Current practice is to determine the total heat loss of an application, desired fuel source, domestic hot water (DHW) generation (if desired), and the radiation pattern. An appropriate boiler selection is made to complement the total radiation and domestic hot water (DHW) (if included). Distribution component selection follows to appropriately interface the boiler to radiation. The hydronic heating system components are subsequently aggregated at the site and assembled piece-by-piece along with interconnection materials. The method is skill, labor and material intensive, producing less than ideal hydronic energy performance in both combustion fuel and electrical power consumption. The contemporary consequence is that similarly specified hydronic heating systems vary dramatically in content and performance. The contributing factors are Hydronic Formulae as applied to “Fixed Speed” (or “Set Point”) circulators are inherently compromised, having only incremental product selections to apply to finite applications. The predominant method of using multiple zone circulators typically exceeds the system delivery capacity under aggregate demand conditions, further reducing hydronic distribution efficiency. Alternately, using a circulator serving multiple zone valves affects individual zone satisfaction both under individual and aggregate demand conditions. An inherently inefficient cost reduction practice. Individual installation practitioner practice is the major system performance inhibitor. There is wide latitude of installation practices evidenced by contemporary trade publications and field observations. Hydronic distribution is the element of a total system installation allowing “personal expression” and hence technical abuse, informatively or not.
Hydronic Heating Medium (Hot Water) Attributes
The density of heated water changes with temperature and must be considered in flow calculations. Subsequent expansion of heated water must be compensated in a system to avoid excessive pressure. Ideal pressure in a typical hydronic system is accepted to be approximately One Atmosphere (15PSI). (The same applies to an automotive cooling system, by example.) Pressurization prevents aeration under circulation and overcomes system physical attributes that create hydronic noise and flow disruption. Air elimination is paramount to maintain flow integrity in any hydronic system, typically by mechanical venting on primary system manifolds and at distribution high points, as necessary. Hydronic convection is the natural attribute of heated water to rise and thus convect (flow) in a closed loop. Its negative effect of continuous heating in a hydronic system must be controlled by “flow check” valves that inhibit its effect during unpowered circulation. They necessarily create resistance and contribute to circulation energy consumption. Convection is neither considered nor applied via contemporary hydronic formulae, nor can it be calculated in system applications given the characteristics of contemporary installation practices.
Hydronic Heating Distribution Technology
Natural hydronic convection has been the basis and development of distributed heating from the Roman Age to the adoption of electric pumps (circulators) by the industry a century ago. They were generally referred to as “Gravity Heating Systems”. Powered centrifugal circulation rapidly overcame the prior by allowing dramatic distribution flexibility at a reasonable cost. Hydronic heating distribution utilizing fixed-speed (or “set-point”) circulators have become the industry norm. The recent development and introduction of both ECM (Electronically Commutated Motor) and Delta-T (Differential Temperature) Controlling Circulators are transforming hydronic heating distribution technology. Both ECM Circulators feature high starting torques and dramatically reduced energy consumption. Their operational life expectancies are significantly increased, reducing “torque stall” as the primary fail mode. The Delta-T Circulator is also “intelligent”, as follows: Two externally positioned temperature sensors measure and display the supply and return loop temperatures. A temperature maintenance differential may be set (typically from 5 to 50° F.), and will be maintained by the circulator's infinitely variable speed capability. This translates into a gallons-per-minute hydronic delivery rate. As a reference, it is accepted that approximate 20° F. differential temperature maintenance in common radiation zones provides ideal heat transfer performance. It equates to an approximate 3 to 4 GPM delivery rate, depending upon attributes. Actual wattage use is dynamically calculated and displayed. The Delta-T circulator has five selectable operating modes.
These existing forced hot water heating systems use multiple pumps, valves, and controllers to supply heat. Complexity, reliability, efficiency, and cost issues result in non-optimum performance.
What is needed is an improved heating system that reduces complexity, and increases reliability and efficiency while reducing cost.